THE EARTH. 149 



We know that it is so with regard to vegetables ; 

 and why not also, in general, to man ? Be this as 

 it will, if we are desirous of having water in its 

 greatest purity, we are ordered, by the curious 

 in this particular, to distil it from snow, gathered 

 upon the tops of the highest mountains, and to 

 take none but the outer and superficial part 

 thereof. This we must be satisfied to call pure 

 water ; but even this is far short of the pure un- 

 mixed philosophical element, which, in reality, 

 is nowhere to be found.* 



As water is thus mixed with foreign matter, 

 and often the repository of minute animals, or 

 vegetable seeds, we need not be surprised that, 

 when carried to sea, it is always found to putrefy. 

 But we must not suppose that it is the element 

 itself which thus grows putrid and offensive, but 

 the substances with which it is impregnated. It 

 is true, the utmost precautions are taken to de- 

 stroy all vegetable and animal substances that 

 may have previously been lodged in it, by boil- 

 ing; but, notwithstanding this, there are some 

 that will still survive the operation ; and others, 

 that find their way during the time of its stow- 

 age. Seamen, therefore, assure us, that their 

 water is generally found to putrefy twice at least, 

 and sometimes three times, in a long voyage. 

 In about a month after it has been at sea, when 



[* Water was, till modern times, considered as an elementary or simple 

 substance ; but it is now known to consist of a mixture of oxygen or vital 

 air, and hydrogen or inflammable air. Nine parts by weight of water con, 

 %ist of eight oxygen and one hydrogen. Charcoal possesses many unexpect- 

 ed properties, and among others, that of preserving water from corruption, 

 and of purifying it after it has been corrupted. ] 



